Adsorption is the tendency of accumulation of molecular species at the surface of solid or liquid. Depending upon the nature of bonds or forces of attraction between adsorbate and adsorbent. It is classofied between physisorption and chemisorption.
Which of the following gases is adsorbed most by activated charcoal?

Options

A. `CO_(2)`
B. `N_(2)`
C. `Ar`
D. `C_(2)H_(6)`

Explanation

To determine which gas is adsorbed most by activated charcoal, we need to consider the concept of adsorption and the factors influencing it.

### Step-by-Step Solution:

1. **Understand Adsorption**: Adsorption is the process where molecules (adsorbate) accumulate on the surface of a solid or liquid (adsorbent). It can be classified into two types: physisorption (weak van der Waals forces) and chemisorption (strong chemical bonds).

2. **Identify Factors Influencing Adsorption**: The extent of adsorption depends on the nature of the gas and the adsorbent. A key factor is the gas's ability to be liquefied, which is influenced by its critical temperature.

3. **Critical Temperature**: The critical temperature of a gas is the temperature above which it cannot be liquefied, regardless of the pressure applied. Gases with higher critical temperatures can be more easily liquefied and thus are more readily adsorbed.

4. **Compare Critical Temperatures**: To find out which gas is adsorbed most by activated charcoal, we need to compare the critical temperatures of the given gases. The gas with the highest critical temperature will be adsorbed the most.

5. **Identify the Gas with the Highest Critical Temperature**: Among common gases, carbon dioxide (CO₂) has a critical temperature of 304 K, which is higher than that of other gases typically considered, such as nitrogen (N₂), oxygen (O₂), and methane (CH₄).

6. **Conclusion**: Since CO₂ has the highest critical temperature, it will be the gas that is adsorbed most by activated charcoal.

### Final Answer:
The gas that is adsorbed most by activated charcoal is **carbon dioxide (CO₂)**.

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